1. Field of the Technology
This technology pertains generally to smart wearable devices.
2. Discussion
One type of wearable device measures parameters related to the body, for example pulse rate, or respiration rate, or EMG, or spatial range of limb motion, etc. Accuracy and/or efficiency of such measurements can be affected by placement of the wearable device on the body.
The optimal placement of a wearable device on the body is often not apparent to the user/wearer of the wearable device. This can be due to a number of reasons. For example, the user/wearer would normally not have sufficient knowledge of the signal being measured or the technology being used for measurement, and hence would not know the optimal placement to improve performance of the wearable device via improved signal measurement. From a usability perspective, the user should not be burdened with requirements of such knowledge. Further, even expert users skilled in physiology and biosensors may not be able to ascertain the best position of placement without detailed measurements, since the signals of interest generated or related to the body are not directly observable by the user/wearer. Using the example of an ECG sensing wearable device above, the user may not realize that the wearable device's performance specifications would prevent it from measuring an ECG signal when placed vertically on the person's chest, or in any orientation on a the person's lower arm.
For instance, a smart-watch may not be able to detect if it is worn on the left or right wrist, at which exact position on the arm, how tightly fitting (or loose) on the wrist. Similarly, a set of wearable smart-glasses does not generally have any precise measurement of the wearer's eye distance, nose shape, or position of the branches of the frame around the ears. This has an implication not only to get the most accurate reading for a wearer, but also to adapt the sensing parameters to each individual's morphology. Indeed, today's wearable devices are generally only relying on user-input parameters (e.g. age, gender, height, weight . . . ) to fine-tune their algorithms, but this may be very coarse and imprecise given the unique characteristics of body shapes, internal organs' positioning (and ethnical variations).
Having multiple physical sizes for wearable devices is a primitive solution, but increases the overall cost structure for vendors/OEMs (and distributors) as multiple models have to be carried through. This therefore results in sub-optimal sensing and also the inability for a wearable device to inform the wearer about the fact that it is currently not positioned correctly—or where the optimal position would be in the wearer's unique case.